C2PooledBlockPool is used by VideoFramePool. Currently VideoFramePool
has exponential backoff retry, so we don't need another retry logic in
C2PooledBlockPool. This CL removes the unnecessary retry logic.

Bug: 160110407
Test: tast.arc.VideoDecodeAccel.h264_vm

Change-Id: I73ffd4b27000846eeea1e5bffbedb21e16795593